Assembly of Si-substituted heteropolyoxotantalate architecture

Abstract

The heteropolyoxotantalates (hetero-POTas) represent a fascinating class of compounds characterized by diverse structural variations and outstanding physicochemical properties. However, the development of hetero-POTas remains an intriguing challenge due to factors such as the indigent solubility, the terribly sluggish reaction kinetics, and the high alkaline reaction atmosphere of the POTa category. In this study, the first hetero-POTa containing Si element, Li₇KNa₁₁H₆[Si₂Ta₂₄(O₂)₂₀O₅₂(OH)₉]·85H₂O (1), was created through self-assembly in a neutral solution. The polyoxoanions embrace 5 tetrahedral {[Ta(O₂)O₅]₄}, 4 {TaO₆} and 1 {Si₂O₇} unit. The compound is the largest hetero-POTa at present. Additionally, 1 has a decent proton conductivity performance with proton conductivity of 3.63 × 10⁻³ S cm⁻¹.